Adding Email Disclaimer Text With The IMS Extension In MS Exchange 5.5


The casual nature of email belies the fact that an electronic message is still, in a business context, a legally binding document, and newspaper stories about the legal issues raised by email are becoming increasingly common. While most people can happily dismiss these stories as ‘a sign of the times’, to the Exchange Administrator they can be a potential source of dismay.
In an effort to preempt legal problems, many Exchange Admins like to add a ‘disclaimer’ or ‘footer’ message to their outgoing emails such as that shown in figure 1. Such messages can also have other uses; for example, in some countries there is a legal requirement to display company registration numbers on all outgoing documents.

Fig. 1 – An example of a simple disclaimer.

Having decided upon this course of action, most Administrators then fire up the Admin.exe program and spend an hour or so searching through the myriad of available configuration options looking for the one that appends a bit of text to all outgoing emails. Eventually they give up in disbelief because – you’ve guessed it – there isn’t one!
It’s a regrettable fact that, out of the box, Exchange lacks the option to add a suitable block of text in this way. Many Administrators that have shared this experience will tell you that it can only be done by configuring a signature at each client, or by purchasing a third-party add-on. There may, however, be another solution.
In an attempt to mitigate this rather glaring omission, Microsoft have partially redeemed themselves by produced the IMS Extension, IMSEXT.DLL. The IMSEXT.DLL is available in several places; most notably the Back Office Resource Kit, Exchange Resource Kits, MSDN and TechNet, and no doubt there are other sources, too.
The IMS Extension can do several things such as Message Journalling, and prepending and appending text to incoming and outgoing Internet email. The feature we are most interested in is the last mentioned one – appending text to outgoing Internet email. You should be aware that since it is an IMS  extension it only works with Internet   email.
Unfortunately, since it requires direct manipulation of the registry in order to make it work, it is not known for its user-friendliness, so if you don’t feel comfortable tinkering with your registry entries then please read no further, otherwise back it up now  and let’s proceed.


Before you begin, you need to be aware that the message in this article is intended only as an example.  It is very unlikely that this particular message will satisfy all your legal requirements, so you will need to compose a message that is more applicable to your organization and its business. The configuration described also requires that Exchange has had at least Service Pack 1 applied.
Having concocted a suitable message, you will then need to obtain a copy of copy of IMSEXT.DLL and decide where to put it. For the purposes of this article, I’ll assume that you have put it in the same directory as the Internet Mail Connector, which is likely to be:
The next thing you need to do is to register the DLL in Windows NT. Open a command prompt window, navigate to the directory containing the DLL and register it with regsvr32 by issuing the following commands:
cd c:\exchsrvr\connect\msexcimc\bin
regsvr32 imsext.dll

Fig. 2 – Registering the IMS Extension DLL.

Next, you will need to make a small modification to your IMC configuration in the Exchange Administrator program. Expand the Directory tree in the left-hand window until you can see the Connections container. Click on the Connections container.

Fig. 3 – The IMC in the Connections container.

Double-click the IMC to open its property pages and then click on the ‘Routing’ tab to reveal the Routing property page shown in figure 4. You need to specify that the IMS Extension is the custom routing program for the IMC, but you have to leave the checkbox next to ‘Instead of the table, use this custom routing program:’ unchecked, otherwise your routing table will be disabled. It is a feature of the service pack that allows us to use IMSEXT as the routing program (by means of the registry entries) and still retain a working routing table.
To make the configuration, then, you need to check the checkbox, click the Browse button, navigate to the directory containing the DLL, and finally uncheck the checkbox again.

Fig. 4 – The Routing property page of the IMC.

Next, you will need to create two registry values. You can either create them directly in regedit, or create a .REG file and merge the contents by double-clicking on it.
The values that you need to create are:
A string value named NonRoutingExtensionDLL in
Its value should be the full pathname to the DLL, i.e.
And a string value named OutBoundAppend in
(You will need to create the ‘Extension’ key)
Its value should be the text, in Rich-Text Format, of the message you wish to append to your outgoing emails. IMSEXT only supports a small subset of RTF, so you cannot use it to specify fonts etc., but you should be aware that carriage returns are entered as \par , followed by a space.
If you wish to take the .REG file route, you can do this in Notepad as shown in figure 5. You should note that in this illustration, Notepad has word-wrap turned off so that you can see it more clearly. There are actually only seven keyboard-typed new lines in the file (they are marked with a red dot in figure 6), you should NOT enter line-feeds while you are typing in the message text. Also note that the backslash character \ needs to be entered twice in .REG file string values, so \par needs to be entered as \\par . Please check and double-check your typing before you attempt to merge it.

Fig. 5 – Creating a .REG file in Notepad (word-wrap view).

Fig. 6 – Line-feeds should only be typed at the places marked in red.

Lastly, you need to stop and restart the MS Internet mail Service using the Services applet in the Windows NT Control Panel.

Fig. 7 – The IMC restart warning message.

Once the IMC has been restarted, if everything has gone according to plan you should find that the text you specified is being appended to all your outgoing Internet email.

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